1939 A Piston Question

[Earl T]

I have tried doing a search for the information, but just couldn't find what I am looking for. Picked up a 1939 A the other day for my son. He has it tore down to the block and with some measuring its still standard bore, but wore out. MY question is would gas pistons from a late A (A3435R) work well or should I just pony up the money for the shinny new aluminum pistons? The tractor still has the correct flat head on it. I would think there should be a compression increase. I don't have a set to measure the height difference. Thanks Earl

 

[kdl]

yes the mid a pistons will work - I have a 1939 a that I used 1940 pistons in and worked fine. the pin bore in the rods will need to be honed larger for the mid a piston pin as it is larger this is not a big deal at all for your machine shop. my 1939 is early ser # so it has unstyled engine (309) the 1940 pistons I used are for the mid a (321 ci) and yes the compression height is higher on the mid a piston so it will slightly increase the compression. it worked great for me it should work fine for you - good luck